#pragma once
#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
#include<list>
#include<string.h>
#include<algorithm>
#include <iostream>
#include<assert.h>
using namespace std;
namespace bit
{
	template<class T>
	struct list_node
	{
		list_node<T>* _next;
		list_node<T>* _prev;
		T _val;

		list_node(const T& val = T())
			:_next(nullptr)
			, _prev(nullptr)
			, _val(val)
		{}


	};

	template<class T, class Ref, class Ptr>
	struct __list_iterator
	{
		typedef list_node<T> Node;
		typedef __list_iterator<T, Ref,Ptr> self;
		Node* _node;
		__list_iterator(Node* node)
			:_node(node)
		{}
		Ref operator*()
		{
			return _node->_val;
		}
		Ptr operator->()
		{
			return &_node->_val;
		}
		self& operator++()
		{
			_node = _node->_next;
			return *this;
		}

		self operator++(int)
		{
			self tmp(*this);
			_node = _node->_prev;
			return tmp;
		}

		self& operator--()
		{
			_node = _node->_prev;
			return *this;
		}

		self operator--(int)
		{
			self tmp(*this);
			_node = _node->_next;
			return tmp;
		}

		bool operator!=(const self& it) const
		{
			return _node != it._node;
		}
		bool operator==(const self& it) const
		{
			return _node == it._node;
		}
	};

	/*template<class T>
	struct __list_const_iterator
	{
		typedef list_node<T> Node;
		Node* _node;
		__list_const_iterator(Node* node)
			:_node(node)
		{}
		const T& operator*()
		{
			return _node->_val;
		}
		__list_const_iterator<T>& operator++()
		{
			_node = _node->_next;
			return *this;
		}

		__list_const_iterator<T> operator++(int)
		{
			__list_iterator<T> tmp(*this);
			_node = _node->_next;
			return tmp;
		}

		bool operator!=(const __list_const_iterator<T>& it)
		{
			return _node != it._node;
		}
		bool operator==(const __list_const_iterator<T>& it)
		{
			return _node == it._node;
		}
	};*/

	template<class T>
	class list
	{
		typedef list_node<T> Node;
	public:
		typedef __list_iterator<T, T&, T*> iterator;
		typedef __list_iterator<T, const T&, const T*> const_iterator;
		//typedef __list_const_iterator<T> const_iterator;



		iterator begin()
		{
			return iterator(_head->_next);
		}
		iterator end()
		{
			return iterator(_head);
		}

		const_iterator begin() const
		{
			return const_iterator(_head->_next);
		}
		const_iterator end() const
		{
			return const_iterator(_head);
		}



		void empty_init()
		{
			_head = new Node;
			_head->_prev = _head;
			_head->_next = _head;

			_size = 0;
		}

		list()
		{
			empty_init();
		}

		list(const list<T>& lt)
		{
			empty_init();
			for (auto& e : lt)
			{
				push_back(e);
			}
		}

		void swap(list<T>& lt)
		{
			std::swap(_head, lt._head);
			std::swap(_size, lt._size);
		}

		list<T>& operator=(list<T> lt)
		{
			swap(lt);
			return *this;
		}

		~list()
		{
			clear();
			delete _head;
			_head = nullptr;
		}

		void clear()
		{
			iterator it = begin();
			while (it != end())
			{
				it = erase(it);
			}
			_size = 0;
		}

		void push_back(const T& x)
		{
			/*Node* tail = _head->_prev;
			Node* newnode = new Node(x);

			tail->_next = newnode;
			newnode->_prev = tail;
			newnode->_next = _head;
			_head->_prev = newnode;*/

			insert(end(), x);
		}

		void push_front(const T& x)
		{
			insert(begin(), x);
		}

		void pop_back()
		{
			erase(--end());
		}

		void pop_front()
		{
			erase(begin());
		}

		iterator  insert(iterator pos, const T& x)
		{
			Node* cur = pos._node;
			Node* prev = cur->_prev;
			Node* newnode = new Node(x);

			prev->_next = newnode;
			newnode->_next = cur;
			cur->_prev = newnode;
			newnode->_prev = prev;

			++_size;
			return newnode;
		}

		iterator  erase(iterator pos)
		{
			assert(pos != end());
			Node* cur = pos._node;
			Node* prev = cur->_prev;
			Node* next = cur->_next;

			prev->_next = next;
			next->_prev = prev;
			delete cur;

			--_size;
			return next;
		}

		size_t size()
		{

			return _size;
		}

	private:
		Node* _head;
		size_t _size;
	};

	void Print(const list<int>& lt)
	{
		list<int>::const_iterator it = lt.begin();
		while (it != lt.end())
		{
			//(*it) += 1;
			cout << *it << " ";
			++it;
		}
		cout << endl;
	}

	void test_list1()
	{
		list<int>lt;
		lt.push_back(1);
		lt.push_back(2);
		lt.push_back(3);
		lt.push_back(4);
		list<int>::iterator it = lt.begin();
		while (it != lt.end())
		{
			(*it) += 1;
			cout << *it << " ";
			++it;
		}
		cout << endl;


		for (auto e : lt)
		{
			cout << e << " ";
		}
		cout << endl;

		Print(lt);
	}

	struct A
	{
		A(int a1 = 0, int a2 = 0)
			:_a1(a1)
			, _a2(a2)
		{}
		int _a1;
		int _a2;
	};

	void test_list2()
	{
		list<A>lt;
		lt.push_back(A(1, 1));
		lt.push_back(A(2, 2));
		lt.push_back(A(3, 3));
		lt.push_back(A(4, 4));

		list<A>::iterator it = lt.begin();
		while (it != lt.end())
		{
			cout << it->_a1 << " " << it->_a2 << endl;
			++it;
		}
		cout << endl;

	}

	void test_list3()
	{
		list<int>lt;
		lt.push_back(1);
		lt.push_back(2);
		lt.push_back(3);
		lt.push_back(4);
		lt.push_front(5);
		lt.push_front(6);
		lt.push_front(7);
		lt.push_front(8);
		for (auto e : lt)
		{
			cout << e << " ";
		}
		cout << endl;
		lt.pop_front();
		lt.pop_back();
		for (auto e : lt)
		{
			cout << e << " ";
		}
		cout << endl;

		lt.clear();
		lt.push_back(10);
		lt.push_back(20);
		lt.push_back(30);
		lt.push_back(40);
		for (auto e : lt)
		{
			cout << e << " ";
		}
		cout << endl;

		cout << lt.size()<<endl;
	}

	void test_list4()
	{
		list<int>lt;
		lt.push_back(1);
		lt.push_back(2);
		lt.push_back(3);
		lt.push_back(4);
		for (auto e : lt)
		{
			cout << e << " ";
		}
		cout << endl;

		list<int> lt1(lt);
		for (auto e : lt1)
		{
			cout << e << " ";
		}
		cout << endl;
		list<int>lt2;
		lt2.push_back(10);
		lt2.push_back(20);
		lt2.push_back(30);
		lt2.push_back(40);
		for (auto e : lt2)
		{
			cout << e << " ";
		}
		cout << endl;
		lt1 = lt2;
		for (auto e : lt1)
		{
			cout << e << " ";
		}
		cout << endl;

	}
}
